What if climate change and pandemics were the real causes of the decline of the Roman Empire? Scientists from a range of disciplines are accumulating clues to show that three successive waves of deadly epidemics and powerful temperature drops could have caused the collapse of the Empire — and draw frightening parallels to today.

Recent discoveries, including funerary urns with highly decorative patterns, and technological advances like the remote sensor system known as LiDAR, are shedding new light on our understanding of pre-Columbian societies in the Amazon. Scientists speculate the rainforest was home to between 8 and 10 million people living in large, well-established communities.